/* Store the signal to real part of fft_input
* and set the image part of fft_input to 0.
*/
void fft_input_init( int16_t *data )
{
int i;
for ( i = 0; i < DATA_LENGTH; ++i )
{
arm_q15_to_float( &data[i], &fft_input[i].real, 1 );
fft_input[i].imag = 0.0f;
}
}
/**
* \brief DSP task core function.
*
* \param pvParameters Junk parameter.
*/
static void dsp_task(void *pvParameters)
{
uint32_t i, j;
uint32_t adc_potentiometer = 0;
const float32_t display_factor = 700;
float32_t bin;
float32_t tmp;
/* Just to avoid compiler warnings. */
UNUSED(pvParameters);
/* Wait for user to read instructions. */
WAIT_FOR_TOUCH_EVENT;
dsp_configure_button2();
dsp_configure_tc();
dsp_configure_adc();
dsp_configure_dacc();
dsp_sin_init();
/* Enable PDC transfer. */
dsp_clean_buffer(dacc_out_buffer[0], SAMPLE_BLOCK_SIZE);
dsp_clean_buffer(dacc_out_buffer[1], SAMPLE_BLOCK_SIZE);
dsp_clean_buffer(dacc_out_buffer[2], SAMPLE_BLOCK_SIZE);
g_pdc_packet.ul_addr = (uint32_t) dacc_out_buffer[0];
g_pdc_packet.ul_size = SAMPLE_BLOCK_SIZE;
g_pdc_nextpacket.ul_addr = (uint32_t) dacc_out_buffer[1];
g_pdc_nextpacket.ul_size = SAMPLE_BLOCK_SIZE;
pdc_tx_init(dacc_pdc, &g_pdc_packet, &g_pdc_nextpacket);
pdc_enable_transfer(dacc_pdc, PERIPH_PTCR_TXTEN);
/* Start Timer counter 0 channel 0 for ADC-DACC trigger. */
tc_start(TC0, 1);
/** DSP task loop. */
while (1) {
/* Using input wave signal. */
if (g_mode_select == 1) {
if (xSemaphoreTake(dacc_notification_semaphore,
max_block_time_ticks)) {
/* Copy dsp_sfx into wav_in_buffer and prepare Q15 format. */
for (i = 0, j = 0; i < 512; ++j) {
tmp = (((dsp_sfx[offset] - (float) 128)) / 100);
/* Store Audio sample real part in memory. */
wav_in_buffer[i++] = tmp;
/* Store Audio sample imaginary part in memory. */
wav_in_buffer[i++] = 0;
/* Prepare buffer for DACC. */
dacc_out_buffer[cur_dac_buffer][j] = (uint16_t)((tmp * 100
* sin_buffer[slider_pos][j]) + 128);
/* Update the wave file offset pointer. */
if (offset < dsp_sfx_size - 1) {
offset++;
} else {
offset = WAVE_OFFSET;
}
}
} else {
/* Ensure we take the semaphore. */
continue;
}
} else {
/* Using generated input sinus signal. */
if (xSemaphoreTake(dacc_notification_semaphore,
max_block_time_ticks)) {
/*
* Read potentiometer value and generate
* sinus signal accordingly.
*/
adc_potentiometer_old = adc_potentiometer;
adc_potentiometer = (afec_channel_get_value(AFEC0,
ADC_CHANNEL_POTENTIOMETER));
adc_potentiometer = adc_potentiometer * 10000 / 4096;
if (adc_potentiometer > adc_potentiometer_old &&
adc_potentiometer -
adc_potentiometer_old < ADC_POTENTIOMETER_NOISE) {
adc_potentiometer = adc_potentiometer_old;
} else if (adc_potentiometer_old > adc_potentiometer &&
adc_potentiometer_old -
adc_potentiometer < ADC_POTENTIOMETER_NOISE) {
adc_potentiometer = adc_potentiometer_old;
}
/* Generate the sinus signal. */
dsp_sin_input(adc_potentiometer);
/* Prepare buffer for DACC. */
for (i = 0, j = 0; i < 512; ++j, i += 2) {
/*
* 2048 is the 0 position for DACC.
* 50 is an amplification factor.
*/
dacc_out_buffer[cur_dac_buffer][j] =
(uint16_t)((wav_in_buffer[i] * sin_buffer[slider_pos][j])
* 50 + 2048);
}
}
}
afec_start_software_conversion(AFEC0);
/* Perform FFT and bin Magnitude calculation */
arm_float_to_q15(wav_in_buffer, cfft_q15, SAMPLE_BLOCK_SIZE * 2);
arm_cfft_radix4_init_q15(&cfft_instance, SAMPLE_BLOCK_SIZE, 0, 1);
arm_cfft_radix4_q15(&cfft_instance, cfft_q15);
arm_cmplx_mag_q15(cfft_q15, mag_in_buffer_q15, SAMPLE_BLOCK_SIZE);
arm_q15_to_float(mag_in_buffer_q15, mag_in_buffer, 128);
/*
* Prepare bins rendering for web page and display.
* Limit to 99, even if we got 128 magnitudes to display.
* Bins are printed using col, incremented by mean of 2 to keep
* a clean rendering. Hence we cannot render all the magnitudes,
* because of the screen width. It would require a 128*2 space.
*/
for (i = 0; i < 99; ++i) {
bin = (mag_in_buffer[i] * display_factor);
if (bin > 0) {
if (bin > 98) {
bin = 98;
}
mag_in_buffer_int[i] = (uint32_t)bin;
} else {
mag_in_buffer_int[i] = 0;
}
}
/* Notify GFX task to start refreshing screen (if necessary). */
if (g_mode_select == 1 || (g_mode_select == 0 &&
adc_potentiometer != adc_potentiometer_old)) {
xSemaphoreGive(gfx_notification_semaphore);
}
}
}
